Short period less than 48hrs was on time but a week later im being told the lining of my womb is to thick so it couldn't have been. confused?

Not a real period: First, did you rule out pregnancy? It's possible that you had 2 days of bleeding but that it was not a normal cycle. You normally menstruate 14 days after ovulation and completely shed your lining. If you don't ovulate, the lining gets thicker and thicker and more disorganized, and eventually some will drift out by accident. But without the proper hormonal trigger the entire lining doesn't shed.